The precise measurement of the moisture content of a material is important in engineering and also in industries dealing with food, cosmetics, tobacco and metal castings, to name a few.
Measurements in the field are often valuable in civil engineering such as in the measurement of the moisture content of ground soil prior to preparing the land for a road.
Among the known methods for the measurement of moisture content are those which involve heating of the sample using a frying pan, a microwave oven or an infrared heater. Soil may be burned by first impregnating the soil with alcohol, igniting the sample, and measuring the weight difference in weight before and after this process. Neutron bombardment of hydrated soil allows calculation of the quantity of water molecules present because water molecules appear on the circumferential surface after neutron bombardment.
The prior art methods for the measurement of moisture content have several known problems which limit their usefulness. Heating according to Japanese Industrial Standards requires a total of 8 hours and alternative standard methods require heating for at least 15-20 minutes. These time frames are impractical if they are to be used at the site of sample collection.
If the temperature is raised above that specified in the standard methods, the temperature may be high enough to cause decomposition of the organic matter which is present in many samples, resulting in the formation of additional water and of oxide compounds. The loss of water and the formation of heavier derivative material results in an inaccurate measurement.
When a burner is used to directly heat the substance, localized overhydration and underhydration of the material is known to occur.
Microwave ovens are not a practical alternative to the direct application of heat because, as the material dries, the cavity no longer contains sufficient amounts of water to absorb the radiation and the "empty-frying" of the sample results in early failure of the equipment.